a couch in the office of a casting director, supposedly used with actors or actresses willing to trade sexual favors for roles.
Origin of casting couch
First recorded in 1940–45
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
informal a couch on which a casting director is said to seduce women seeking a part in a film or play
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012